It is well known that phyllosilicates, such as smectite clays, e.g., sodium montmorillonite and calcium montmorillonite, can be treated with organic molecules, such as organic ammonium ions, to intercalate the organic molecules between adjacent, planar silicate layers, for bonding the organic molecules with a polymer, for intercalation of the polymer between the layers, thereby substantially increasing the interlayer (interlaminar) spacing between the adjacent silicate layers. The thus-treated, intercalated phyllosilicates, having interlayer spacings increased by at least 3 Å, preferably at least 5 Å, e.g., to an interlayer (interlaminar) spacing of at least about 10-25 Å and up to about 100 Angstroms, then can be exfoliated, e.g., the silicate layers are separated, e.g., mechanically, by high shear mixing. The individual silicate layers, when admixed with a matrix polymer, before, after or during the polymerization of the matrix polymer, e.g., a polyamide—see U.S. Pat. Nos. 4,739,007; 4,810,734; 5,385,776; 6,232,388; and published application 2005/0009976 A1—have been found to substantially improve one or more properties of the polymer, such as mechanical strength and/or high temperature characteristics.
Exemplary prior art composites, also called “nanocomposites”, are disclosed in this assignees U.S. Pat. No. 6,232,388, and in published applications 2005/0009976 A1 ('976) and 2004/0224112 A1 ('112). The '976 published application describes a gas barrier polyamide composition that includes a combination of a crystallizable polyamide and an amorphous polyamide that resists delamination from surrounding PET layers of a bottle, has a reduced Tg and reduced crystallinity, but sacrifices gas barrier properties. The '112 published application describes a modified PET resin in a multilayer container.
In accordance with one embodiment of the intercalates, articles and methods described herein, intercalates are prepared by contacting a phyllosilicate with a monomeric onium ion spacing/coupling agent compound. To achieve the fill advantage of the present invention, the onium ion should include at least one long chain radical (C6+) that may be aliphatic, straight or branched chain, or aralkyl. Exemplary of such suitable C6+ onium ion molecules include primary, secondary, tertiary or quaternary ammonium ions, sulfonium ions, phosphonium ions, oxonium ions, or any ion of an element in Groups V or VI of the periodic table of elements.
In accordance with an important feature of the intercalates, articles and methods described herein, best results are achieved by mixing the layered material with the onium ions, e.g., C6+ onium ion spacing/coupling agent, in a concentration of at least about 2% by weight, preferably at least about 5% by weight onium ion compound, more preferably at least about 10% by weight onium ion compound, and most preferably about 30% to about 80% by weight, based on the weight of onium ion compound and carrier (e.g., water, with or without an organic solvent for the onium ion compound) to achieve better sorption of the onium ion spacing/coupling agent compound between the platelets of the layered material. Regardless of the concentration of onium ion compound in the intercalating composition, the weight of the onium ion intercalated clay should be about 0.5% to about 10%, preferably about 1% to about 7% most preferably about 2% to about 5%, based on the total weight of matrix polymer plus onium ion-intercalated clay. The compositions can be initially formed as concentrates having up to about 90% intercalated clay that can be diluted with additional matrix polymer to form the final compositions.
In accordance with an important feature of the intercalates, articles and methods described herein, it has been found that an onium ion-intercalated phyllosilicate, such as a smectite clay, can be intercalated easily with aromatic polyamide and polyphenoxy intercalants to form an onium ion aromatic polyamide and/or polyphenoxy matrix polymers polyamide and polyphenoxy intercalant co-intercalate that has excellent intercalate dispersibility in a matrix polymer, particularly an aromatic polyamide, e.g., MXD6 nylon, and/or polyphenoxy matrix polymer and has unexpectedly low gas (particularly O2) permeability in an aromatic polyamide and/or polyphenoxy matrix polymer. The preferred proportions of polyphenoxy and aromatic polyamide intercalants are about 1% to about 20% by weight, preferably about 5% to about 10% by weight polyphenoxy and about 80% to about 99% by weight, preferably about 90% to about 95% by weight aromatic polyamide. The intercalate also can be added to any other matrix polymer to enhance a number of properties of the matrix polymer, including tensile strength, heat distortion temperature, gas-impermeability, elongation, and particularly adhesion of the polymer to an adjacent polymer layer.
The onium ion/aromatic polyamide and/or polyphenoxy co-intercalates and/or exfoliates thereof can be admixed with a polymer or other organic monomer compound(s) or composition to increase the viscosity of the organic compound or provide a matrix polymer/intercalate and/or matrix polymer/exfoliate composition to enhance one or more properties of the matrix polymer, particularly an MXD6 nylon matrix polymer.
The onium ion/aromatic polyamide and/or polyphenoxy co-intercalates can be added, particularly by direct compounding (mixing the intercalate directly into a matrix polymer melt) of the intercalate with any matrix polymer, e.g., all market available resin systems, particularly epoxy resins such as: Bisphenol A-derived resins, Epoxy cresol Novolac resins, Epoxy phenol Novolac resins, Bisphenol F resins, polynuclear phenol-glycidyl ether-derived resins, cycloaliphatic epoxy resins, aromatic and heterocyclic glycidyl amine resins, tetraglycidylmethylene-dianiline-derived resins, nylons, such as nylon-6 and nylon 66, and particularly MXD6 nylon.